Operators perform completion operations during the life of a well to access hydrocarbon reservoirs at various elevations. Completion operations may include pressure testing the tubing, setting a packer, activating safety valves, or manipulating sliding sleeves. In certain operations, it may be desirable to isolate one portion of the completion from another. Typically, an isolation valve having an internal ball valve is disposed in the completion to isolate portions of the well. One example of such an isolation valve is the completion isolation valve (CIV) from Weatherford.
FIG. 1A shows a completion isolation valve 10 in an opened condition with the ball valve 20 allowing flow through the valve's bore 12. When running a tool string through the open valve 10, operators insert a profiled stinger 30 on the end of the tool string into the valve 10 as shown in FIG. 1B. The stinger 30 engages dogs 16 in the valve 10. Downward movement of the stinger 30 engaged by the dogs 16 then moves a shifting mechanism 14 to lock the internal ball valve 20 open. Once the valve 10 is opened, a tool string can be passed through the valve 10 to work on the lower completion. To remove the tool string, operators lift the profiled stinger 30 at the end of the string back into the valve 10. As shown in FIG. 1C, the stinger 30 raised in the upward direction closes the internal ball valve 20 by engaging the dogs 16 as the stinger 30 passes up through the valve 10.
Although effective in isolating portions of a completion, valves using internal ball valves have several drawbacks. For example, ball valves require a large wall thickness to house it. The increased wall thickness required by a ball mechanism makes it have either a smaller ID or a larger OD than the flapper designs. To overcome such drawbacks, isolation valves have been developed that use flappers to isolate portions of a completion. One example of such a valve having dual flappers is the Optibarrier available from Weatherford and disclosed in U.S. patent application Ser. No. 11/761,229, entitled “Dual Flapper Barrier Valve,” which is incorporated herein by reference in its entirety.
In many valves used downhole, operators use shifting sleeve profiles to mechanically actuate the valve open and closed. Unfortunately, operators deploying a tool downhole to mechanically actuate the valve may inadvertently miss engaging the profile during run in. In such a circumstance, the tool string may slip through and run into the closed valve, damaging the closure device and rendering the valve inoperable. To avoid this, operators must pay careful attention while running a tool in the hole so as not to damage any downhole valves.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.